Thursday, May 21, 2009

Film Vs Digital Lenses

A standard 50mm lens.








Many camera manufacturers now produce lenses that are designed solely for digital cameras. These lenses are not compatible with traditional 35mm film SLRs, despite modern digital SLR bodies being compatible with older lenses. It is important to take your camera type, shooting habits and future upgrade plans into consideration when deciding between a new digital or traditional lens.


Digital SLR Camera Conversion Factor


A digital SLR camera.


Many digital SLRs use sensors with a smaller frame size than 35mm film. APS-C are popular sensors used in many digital SLR cameras. The format has been adopted for the consumer and semi-professional camera market. There is a crop factor when using a traditional 35mm lens with an APS-C censor. The digital image will include a margin of the scene that was beyond the boundary of the viewfinder. The conversion factor also changes the actual focal length of a lens. The focal length of a 24mm lens becomes approximately a 35mm focal length.


Digital Lenses


A digital lens.








Lenses created specifically for digital cameras correct the crop factor created by APS-C sensors. Digital lenses have a smaller frame to match the frame size of the small sensor, Ken Rockwell said in an article on the Nikon DX format. Many manufacturers have their own sensor formats that use the APS-C standard: Nikon's DX format, Canon's EF-S lenses and Olympus' FourThirds system.


35mm Lenses


A 35mm telephoto lens.


Many lenses made for 35mm cameras have manual aperture control directly on the lens. Make sure to lock in the aperture setting on the lens so that it can be controlled by the camera's buttons. Some manufacturers have introduced cameras such as Nikon's D40 that do not support auto-focus on older lenses. Many photographers exploit certain aberrations in older lenses for creative purposes.


Digital Full-Frame


A digital SLR camera.


Camera manufactorers now off full frame sensors---a sensor the same size as 35mm film. The result is more information captured on a larger surface. Images can be printed larger and with grater detail. Nikon's FX format was the world's first full-frame digital sensor that eliminates the crop factor created by APS-C sensors. Canon uses full-frame sensors in their 5D and 1D series cameras. Sony released the A850 with full-frame capabilities. Full frame senors give photographers the true focal length of their lenses. Some full-frame digital cameras, such as Nikon's D3, automatically adjust for digital (DX) lenses.


Considerations


A roll of 35mm film.


Digital lenses provide consumers with a way of getting the most out of an APS-C sensor. For those looking to continue using the APS-C format, digital lenses will provide true focal lengths and compatibility. With regards to the format's survival, Photo.net columnist Bob Atkins says, "if 24 x 36mm sensors had been available for the same price as 22 x 15mm sensors do you think anyone would have made a camera with the smaller sensor?"

Tags: 35mm film, digital cameras, focal length, crop factor, Nikon format